The present invention relates generally to a continuous and discontinuous discharge of glass melts from a ceramic glass melting furnace in which highly radioactive wastes are to be melted into the glass, with it being possible to measure the volume of glass flow of the melt and to start and stop it at will. More particularly, the invention relates to a discharging device in the bottom of such a glass melting furnace.
The glass melt in such a furnace flows out in liquid state through a special glass discharge channel. When the temperature of the melt drops below the melting temperature, the melt solidifies into solid glass and thus closes the discharge path. In this type of discharging device, the required temperatures are generally generated by inductive heating.
German Pat. No. 2,842,505, as well as corresponding U.S. Pat. No. 4,402,724, discloses a discharging device for a glass melting furnace for radioactive wastes in which difficulties may arise at the start of the glass flow, when the solidified glass is melted, in that temperature fluctuations or temperatures of an insufficient magnitude occur locally. In another discharging device, which is improved over the cited prior art with respect to its starting characteristics in that the discharging device is moved toward the interior of the furnace, the higher temperature levels frequently cause leakage problems in that the glass creeps around the outlet unit of the discharging device. These leakages have been found to occur after several years of use of such discharging devices.